Central Nervous System Imaging in Rheumatic Diseases

A summary of CNS complications seen in rheumatic disorders is presented in Table 1. When evaluating a patient with a rheumatic disease, it is important to look for neurologic symptoms and obtain further imaging when needed. Early diagnosis of these conditions leads to earlier treatment and therefore decreased disability. When there are concerns for cerebrovascular disease, CT scan, MRI, and vessel imaging are part of the diagnostic workup. CT scan is more sensitive in the detection of hemorrhage, while MRI with DWI sequences is the modality of choice for ischemic infarcts. Moreover, other conditions such as CVST and PRES may be seen on MRI. Vessel imaging is done to assess the integrity of CNS vessels and evidence of stenoses, occlusion, aneurysm, dissection, or vasculitis. CTA, MRA, and DSA are the angiographic studies routinely used in practice. CTV and MRV are the imaging modalities of choice for CVST. When the presentation is concerning for a vasculitic process, high- resolution MRI with vessel wall imaging may be of value. Lastly, Doppler ultrasound is used for large-vessel vasculitides. For evaluation of parenchymal diseases such as demyelinating conditions and lesions and optic neuritis, brain MRI with gadolinium contrast is the modality of choice. MRI of the cervical, thoracic, and lumbar spine with gadolinium contrast is used for workup of myelitis. MRI of orbit is more sensitive to show changes in the optic nerve. Similarly, for assessment of pituitary involvement, brain MRI is a diagnostic modality. In diseases such as RA that lead to spinal instability and compression myelopathy, spinal CT scan is the modality of choice to visualize bony changes. Spinal MRI may also be used to assess the extent of myelopathy and soft tissue abnormalities. For headache disorders, imaging is usually not necessary unless the rheumatic condition is associated with hypercoagulable state or higher chances of secondary headache disorders such as CVST or IIH. In these cases, CTV or MRV would be needed to rule out these secondary causes. For aseptic meningitis, the clinical workup is usually focused on CSF studies. However, MRI brain with gadolinium contrast may show meningeal enhancement. To assess meningeal diseases such as pachymeningitis or leptomeningitis, MRI brain with IV contrast is the modality of choice. Seizures, as a common presentation of rheumatic diseases, may be lesional or nonlesional. Given the probability of lesional causes (such as CVST and PRES), for new- onset seizures, obtaining neuroimaging is necessary. Similarly, movement disorders such as chorea may be caused in the setting of CNS lesions among these patients and need further workup with neuroimaging.